2nd Deep-Water Circulation Congress, 10-12 Sept. 2014, Ghent, Belgium
The Kveithola Drift (western Barents Sea): Preliminary results from the CORIBAR Cruise
Till J.J. Hanebuth1,3, Rebesco M.2, Grave M.1, Özmaral A.1, Lucchi R.G.2 and the CORIBAR Team
1
2
3
MARUM – Center for Marine Environmental Sciences, University of Bremen, 28369 Bremen, Germany. thanebuth@marum.de.
OGS (Istituto Nazionale di Oceanografia e di Geofisica Sperimentale), Sgonico (TS), Italy
Currently at: Geology and Geophysics Dept, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02540, U.S.A.
Abstract: The CORIBAR cruise (08/2013) addressed ice dynamics and meltwater deposits by coring
inside the narrow (100km long, 13km wide) glacially eroded Kveithola Trough, NW Barents Sea. During
this cruise, geophysical data (PARASOUND sub-bottom and multibeam profiles) and sediment cores were
also collected from the Kveithola Drift. This drift is a complex morphological sediment body confined to
the innermost part of the Kveithola Trough. It consists of two main depocenters separated by a buried
glacigenic grounding-zone wedge. The internal acoustic reflections show a drastic thinning, i.e. longterm condensation, towards the northern flank of the Kveithola Trough. Here, a distinct E-W running
moat is developed which underlines the strong influence of dense bottom currents on sedimentation. On
the contrary, some of the characteristics of sedimentary facies and preserved biota in the surface sediments of the Kveithola Drift hint to a stagnant environment, strongly affected by low-oxygen conditions.
The PARASOUND data and sediment cores from this intriguing sediment drift are expected to contain a
high-resolution record of the drift formation processes as well as the Holocene palaeo-environmental
changes.
Key words: Shallow-water contourites, ice-stream trough, dense-flow cascading, Barents Sea, Holocene.
INTRODUCTION
DATA AND RESULTS
The Kveithola contourite drift is located in the innermost part of the Kveithola Trough. This trough has
formed during the past glacial cycles and extends about
100km from the shallow Barents Shelf towards the open
Norwegian Sea (Fig. 1). The trough is 13km wide and
200m deeper than the surrounding shallow shelf. Whilst
grounding-zone wedges and glaciomarine deposits have
formed during deglacial times (Rebesco et al., 2011;
Bjarnadóttir et al., 2013), a drift body has grown during
post-deglacial times, i.e. after the modern ocean conditions have established on the Barents Shelf (Fig. 2;
Fohrmann, 1996; Bjarnadóttir et al., 2013).
During the CORIBAR expedition (RV Maria S.
Merian, 08/2013), we run a dense grid of PARASOUND
sub-bottom echosounder profiles across the contourite
drift and took 8 sediment cores (Hanebuth et al., 2013).
The aim was to analyse the environmental processes
involved in the history of this depocenter in terms of
bottom-flow pattern and intensity, of material source
and transport routes, and of palaeoceanographic control.
FIGURE 1: Overview map showing the western Barents Sea. Box +
arrow indicate the Kveithola Trough (modified from Andreassen et
al., 2008).
Whether contourite deposition can occur in shallow
waters, i.e. on continental shelves, is debated. Nevertheless, current-controlled sediment bodies in shallow
waters may show a shape and internal geometry very
similar to those found in the deep ocean. We present
here an outstanding example of a contourite drift which
has formed under favourable morphological and bottom-flow conditions inside a partly filled glacigenic
palaeo-ice-stream trough.
The body shows two major depocenter separated by
the transverse-oriented elevation of a buried groundingzone wedge, with the western major accumulation centre being 35m thick. The lateral continuity of the subbottom reflectors in combination with high-resolution
sediment-core scans (magnetic susceptibility, density,
XRF) allows for a dense-spaced and robust correlation
framework.
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2nd Deep-Water Circulation Congress, 10-12 Sept. 2014, Ghent, Belgium
Whilst the southern margin of the contourite body is
rising and attached to the southern flank of the Kveithola Trough, the northern margin is controlled by a welldeveloped moat (Fig. 2). The internal strata pinch out
here and bed condensation clearly indicates how the
confined bottom current has controlled deposition here
from the very beginning.
ACKNOWLEDGEMENT
The CORIBAR team members: A. Camerlenghi and A.
Caburlotto (OGS), T. Hörner (AWI, Bremerhaven), H.
Lantzsch and A. Özmaral (MARUM, Bremen), J. Llopart (CSIC, Barcelona), L.S. Nicolaisen (GEUS, Copenhagen), K. Andreassen and G. Osti (UiTromsø), A.
Sabbatini (UNIVPM, Ancona). CORIBAR is funded by
the Italian PNRA, Spanish “Ministerio Economia y
Competitividad”, Danish Carlsberg Foundation and
Dansk Center for Havforskning, Statoil ASA, and
MARUM incentive. CORIBAR is embedded into the
international NICESTREAM project.
REFERENCES
Andreassen, K., et al., 2008. Seafloor geomorphology of
the SW Barents Sea and its glaci-dynamic implications. Geomorphology 97, 157-177.
Bjarnadóttir, L.R., et al., 2013. Grounding-line dynamics during the last deglaciation of Kveithola, W
Barents Sea, as revealed by seabed geomorphology
and shallow seismic stratigraphy. Boreas 42, 84-107.
Hanebuth, T.J.J., et al., 2013. CORIBAR – Ice dynamics and meltwater deposits: coring in the Kveithola
Trough, NW Barents Sea. Cruise MSM30. 16.07. 15.08.2013, Tromsø (Norway) - Tromsø (Norway).
Berichte, MARUM, Univ. Bremen 299, 74 pp. Bremen, 2013. ISSN 2195-7894.
Rebesco, M., et al., 2011. Deglaciation of the western
margin of the Barents Sea Ice Sheet — A swath
bathymetric and sub-bottom seismic study from the
Kveithola Trough. Marine Geology 279, 141-147.
Fohrmann, H., 1996. Sedimente bodengebundener Dichteströmungen – numerische Fallstudien. Berichte
Sonderforschungsbereich 313, Univ. Kiel 66, 106
pp. ISSN 0942-119X.
FIGURE 2: CORIBAR PARASOUND profile across the inner part of the
Kveithola Drift. Note the abrupt pinch-out of the internal reflectors
towards the northern flank where a pronounced moat has formed. The
locations of some GeoB sediment cores are indicated by red bars.
The contourite body itself shows a two-stage stratigraphic formation history. The upcoming analysis of the
sediment cores, which cover all stratigraphic levels of
the contourite drift, will allow insight into the stratigraphic changes as well as into lateral variability of
bottom sediment transport control for the entire time of
formation.
CONCLUSIONS
A former modelling study has suggested that the
gravity-driven bottom-flow conditions inside the modern Kveithola Trough result in a complex pattern of
bottom-flowing eddies (Fohrmann, 1996). By combining our long-term architectural investigations and shortterm depositional pattern with existing oceanographic
data sets and the former bottom-flow simulation, we
will be able to investigate:
- How this contourite drift has formed
- Which major environmental forces have control on
sedimentation;
- How these conditions have fluctuated on short timescales;
- How they have varied during the past several thousands of years.
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